Prime Minister Julia Gillard suffered another attack on her authority last night through new claims that she distributed polling on her popularity before toppling Kevin Rudd, prompting MPs to declare that Labor’s leadership rivalry would have to be brought to a head.

Ms Gillard was already under fire from within caucus after she admitted yesterday that she had canvassed the challenge with her colleagues weeks before the June 2010 coup and saw a “victory speech” before ­winning the top job.

While Ms Gillard rebuffed questions about whether she knew then of internal polling showing she would make a better leader than Mr Rudd, the Nine Network reported last night that she not only knew of it but also showed it to Labor MPs.

Caucus members expressed dismay at the new claim amid concern that the renewed dispute over old events would inflame the current leadership rivalries and further undermine Ms Gillard’s position.

MPs interpreted the Nine report as a calculated attempt to challenge Ms Gillard’s version of events and weaken her authority even though it was unsurprising that she would have had access to the polling as the party’s deputy leader at the time.

The developments heightened expectations that Mr Rudd would seek to reclaim the leadership despite doubts about the level of his support, with his opponents estimating his numbers at 20 of the 103 caucus votes rather than the 40 sometimes claimed and the 53 he would need to win.

“He is nowhere near critical mass,” one MP said, but he added that the Rudd camp was set on destabilising Ms Gillard and the rivalry needed to be brought to a head.

“I think Kevin does want the job again – it’s an implied position you have with him and his supporters,” Mr Oakeshott, one of the crossbenchers who has an agreement to support Ms Gillard’s minority government, told ABC Radio on Wednesday.

“It’s a reality the government would be better admitting and then getting on with running the country.”

Senator Doug Cameron displayed the mood of many in the caucus, saying the party was paying a price for the way Ms Gillard was installed.

“I said at the time I thought it was the wrong move, that Labor would pay a price for the nature of the change of leader,” he said. “I haven’t changed my mind on that.”

But Ms Gillard’s caucus supporters said there were no revelations in an ABC TV Four Corners program on Monday night to justify the renewed interest in the challenge almost two years ago.

Others cautioned that Ms Gillard’s answers had the potential to weaken her standing among Labor MPs given the belief that she was more ­calculating in the move against Mr Rudd than first appeared.

“I made my decision to ask Kevin Rudd for a leadership ballot on the day that I spoke to him and asked him for that leadership ballot,” Ms Gillard told reporters yesterday.

“I was canvassed in the short days before, very close in to me making that decision.

“When people had sought to raise the matter with me earlier I had declined to have the conversation with them and no amount of speculation here or media interest will change that simple fact that I made up my mind on the day that I asked Kevin Rudd for a ballot.”

While the ABC claimed a speech had been written by Ms Gillard’s staff a fortnight before the Wednesday, June 23, meeting with Mr Rudd, the Prime Minister dismissed that yesterday. “The important thing here in relation to what was on Four Corners last night is: number one, I didn’t direct anybody to write a speech for me. And number two, I made up my mind on the day.”

Earlier, Ms Gillard told ABC Radio it had been a “tense few days” for her and she could not say when she came to know about the speech.

“It could have been the Wednesday night, it could have been before, but the point here is I didn’t direct the speech,” she said.

Ms Gillard said she could not recall the details of any polling in June 2010 that showed her popularity was greater than that of Mr Rudd, although she noted that as deputy leader she saw the poll surveys. “One prominent Labor MP told me this afternoon Ms Gillard not only had the polling but showed it to caucus members, including him in the week leading up to the move against Mr Rudd,” the Nine Network’s ­Laurie Oakes said last night.

Ms Gillard’s supporters acknowledged that the decision to take the claim to Mr Oakes could only be interpreted as a calculated attack on the Prime Minister.

Opinions differed, however, on whether Ms Gillard had actively sought the leadership among her ­colleagues in the weeks before she confronted Mr Rudd.

Senior Labor figures have previously insisted to The Australian Financial Review that she did not canvass for support and was not a candidate for the leadership until the evening it was decided.

One of the factional leaders behind the events, Employment Minister Bill Shorten, responded to the latest reports by telling ABC TV that he had urged Ms Gillard to take the leadership only a few days before it was decided. “She made up her mind on the day,” Mr Shorten said.

Labor’s regular caucus meeting yesterday heard a short speech from Ms Gillard that emphasised jobs and the economy but some of those who attended said there was little new in the remarks.

Regional Minister Simon Crean described Ms Gillard as a “courageous person” for agreeing to the TV interview.